Final answer:
Amir cringes at being called a 'true Afghan' due to feelings of guilt and the betrayal of his close friend, which make him question his worthiness of this title in the context of the novel 'The Kite Runner'.
Step-by-step explanation:
The discomfort expressed by Amir when called a "true Afghan" by Wahid most likely stems from a deep-seated feeling of guilt and unworthiness. Amir, a character from Khaled Hosseini's novel The Kite Runner, struggles with his past actions, particularly his betrayal of a close friend. This makes him question whether he genuinely embodies the values and honor that would make him worthy of being called a 'true Afghan' in Wahid's eyes.
As the context of this question does not align with the provided information about Amir Khan Muttaqi and is more relevant to literature and character analysis, a thorough answer would focus on the emotional and psychological aspects of Amir's character development in the novel.